Fix requested python version

[EvgeniyPatlan]

According to debian control file and according to rpm spec files it is requested to have python at least 3.8

if(HAVE_PYTHON)
  list(APPEND EXTRA_CMAKE_OPTS "-DHAVE_PYTHON=1")
  if (BUNDLED_PYTHON_DIR)
    list(APPEND EXTRA_CMAKE_OPTS "-DBUNDLED_PYTHON_DIR=${BUNDLED_PYTHON_DIR}")
  else()
    list(APPEND DEB_BUILD_DEPS "python3-dev (>= 3.8)")

%if 0%{?rhel} >= 8
BuildRequires:  python38-devel
%else
BuildRequires:  python3-devel >= 3.8
%endif

[mysql-oca-bot]

Hi, thank you for your contribution. Please confirm this code is submitted under the terms of the OCA (Oracle's Contribution Agreement) you have previously signed by cutting and pasting the following text as a comment:
"I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it."
Thanks

[EvgeniyPatlan]

I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

[mysql-oca-bot]

Hi, thank you for your contribution. Your code has been assigned to an internal queue. Please follow
bug http://bugs.mysql.com/bug.php?id=107412 for updates.
Thanks